Firebird oil boiler hot water

[Westernr1]

My firebird oil boiler hw supply is luke warm, but does heat up slightly when run if the ch is on at the same time.
Is this a faulty diverter valve?
If so could I replace this myself as I've heard they're expensive to fix.
Tia

 

[SimonG]

What model firebird? Put a pic up of front with cover off.

 

[Westernr1]

What model firebird? Put a pic up of front with cover off.

 

[Westernr1]

I e also attached a picture of the plate inside

 

[SimonG]

No diverter valve on that model, it uses a twin pump. Are you in a hard water area? Have you tried turning up the blending valve?

 

[Westernr1]

In a soft water area, and yes have tried the blending valve. Have it turned all the way up and water only reading 36 degrees

 

[SimonG]

Is hot water pump operating when hot tap opens?

 

[Westernr1]

Is hot water pump operating when hot tap opens?

Yes pump is spinning.
Have removed the silver screw on the front and made sure it hasn't siezed up.
Gave it a few turns with a small screwdriver.
All good

 

[SimonG]

How hot is the heatstore?

 

[Westernr1]

How hot is the heatstore?

Sorry, not sure about this one?

Heatstore?

 

[exedon2]

Heat store is the steel tank on right had side of boiler pumps in front of it.
Should be hot (too hot to keep your hand on comfortably)

 

[Westernr1]

Heat store is the steel tank on right had side of boiler pumps in front of it.
Should be hot (too hot to keep your hand on comfortably)

Sorry, yes course.......heatstore is hardly hot at all.
Pump is way too hot though when hot tap is run

 

[SimonG]

Sorry, not sure about this one?

Heatstore?

It's the tank behind the pumps, it stores hot water to generate your actually hot water.

 

[Westernr1]

It's the tank behind the pumps, it stores hot water to generate your actually hot water.

Sorry, yes course.......heatstore is hardly hot at all.
Pump is way too hot though when hot tap is run

 

[SimonG]

Could be the heat store thermistor.

 

[Westernr1]

Could be the heat store thermistor.

Have just changed this tonight.....no change.
Could it be the blender valve?

 

[exedon2]

Is the heat store now hot ?

 

[Westernr1]

Is the heat store now hot ?

Not really, the water temp fluctuates, and when I rotate the blender valve backwards and forwards it does get hot for a while. Which is why I was wondering if it was the blender valve?

 

[John.g]

The heat store should still get very hot even if blender valve is faulty. Can you switch off the boiler, run off say 20 or 30 liters of HW, shut the HW tap then fire up the boiler and see how long it runs for.

 

[Westernr1]

The heat store should still get very hot even if blender valve is faulty. Can you switch off the boiler, run off say 20 or 30 liters of HW, shut the HW tap then fire up the boiler and see how long it runs for.

Yes, did that yesterday ran for about 10 mins

 

[John.g]

The 35kw boiler must have sent 5.53 kwh somewhere, assuming.iit's to the store then that's sufficient to raise 125L from 25C to 65C . Are you sure the store isn't very hot? The only other route for that 5.53kwh is to the CH?

 

[Westernr1]

The 35kw boiler must have sent 5.53 kwh somewhere, assuming.iit's to the store then that's sufficient to raise 125L from 25C to 65C . Are you sure the store isn't very hot? The only other route for that 5.53kwh is to the CH?

The store feels mildly warm but not hot

 

[John.g]

Are the boiler CH flow and return pipes hot for this 10 minutes, I can't imagine the heat going anywhere else, any idea, even roughl of the heat store volume?.

 

[John.g]

Can't find a schematic of a Firebird Combi but its probably something like this Grant where the stored water is primary water, might be worth checking the non return valves and that the heating pump isn't running when HW requested. The Grant primary store is 32.5 Litres, total contents 53.5 litres.

 

[John.g]

some of these environmex have two pumps, others don't so maybe diverter valve as you suggested?.
You have two as per your photo!!

 

[SimonG]

Two pumps = no diverter.

Need to know if rads are getting hot when hot waters ran. If so it's a non return valve.

 

[exedon2]

I'm attaching a firebird technical update I got some years ago when we were repairing one ,
Seem to indicate heat store should be 78 C also describes how to test thermistors

 

[John.g]

They claim 120L available at 20LPM at a 40C dT from the 40L primary store (78C) presumably as the boiler will be firing at 35kw output as well.
Any idea of the continuous flowrate at say 40C once the store has fallen to say 50C?, there will obviously be a dT between the PHE and the DHW temperature, is say 16.0/16.5LPM at 40C achievable at a mains/DHW dT of 30C.